THE world in 1950 looked very different from how it does now. Europe was home to 22% of the world's 2.5 billion people. Germany, Britain, Italy and France all counted among the 12 most populous countries. But strong economic growth in Asia coupled with high fertility rates in Africa have contributed to a big regional shift in the global population. The UN's latest World Population Prospects expects the world to grow from 7.2 billion people today to 9.6 billion in 2050.